I think Sonu Nigam has sung great songs in the movie Jaan-e-mann.
' hum ko maloom hai 'a duet with Sadhana Sargam is good,then the sad song
'sau dard'is also good
but I think the best one is 'ajnabee sheher',I simply love the verses of this song.
the qawwali type song 'Jaane ke jaane naa' a duet with sukhwinder singh is also nice.
In my opinion Sonu has done full justice to all these songs.